vue 根据后台给的链接点击直接下载

   //点击时的下载事件
    async choseDownload(url) {
      let image = new Image()
      image.setAttribute('crossOrigin', 'anonymous')
      image.src = url
      image.onload = () => {
        let canvas = document.createElement('canvas')
        canvas.width = image.width
        canvas.height = image.height
        let ctx = canvas.getContext('2d')
        ctx.drawImage(image, 0, 0, image.width, image.height)
        canvas.toBlob((blob) => {
          let url = URL.createObjectURL(blob)
          this.download(url, name)
          // 用完释放URL对象
          URL.revokeObjectURL(url)
        })
      }
    },
    download(href, name) {
      let eleLink = document.createElement('a')
      eleLink.download = name
      eleLink.href = href
      eleLink.click()
      eleLink.remove()
    },